NAME
HTTP::Lite - Lightweight HTTP implementation
SYNOPSIS
use HTTP::Lite;
$http = HTTP::Lite->new;
$req = $http->request("http://www.cpan.org/")
or die "Unable to get document: $!";
print $http->body();
DESCRIPTION
HTTP::Lite is a stand-alone lightweight HTTP/1.1 implementation
for perl. It is not intended as a replacement for the
fully-features LWP module. Instead, it is intended for use in
situations where it is desirable to install the minimal number of
modules to achieve HTTP support, or where LWP is not a good
candidate due to CPU overhead, such as slower processors.
HTTP::Lite is also significantly faster than LWP.
HTTP::Lite is ideal for CGI (or mod_perl) programs or for bundling
for redistribution with larger packages where only HTTP GET and
POST functionality are necessary.
HTTP::Lite supports basic POST and GET operations only. As of
0.2.1, HTTP::Lite supports HTTP/1.1 and is compliant with the Host
header, necessary for name based virtual hosting. Additionally,
HTTP::Lite now supports Proxies.
As of 2.0.0 HTTP::Lite now supports a callback to allow processing
of request data as it arrives. This is useful for handling very
large files without consuming memory.
If you require more functionality, such as FTP or HTTPS, please
see libwwwperl (LWP). LWP is a significantly better and more
comprehensive package than HTTP::Lite, and should be used instead
of HTTP::Lite whenever possible.
CONSTRUCTOR
new This is the constructor for HTTP::Lite. It presently takes no
arguments. A future version of HTTP::Lite might accept parameters.
METHODS
request ( $url, $data_callback, $cbargs )
Initiates a request to the specified URL.
Returns undef if an I/O error is encountered, otherwise the HTTP
status code will be returned. 200 series status codes represent
success, 300 represent temporary errors, 400 represent permanent
errors, and 500 represent server errors.
See http://www.w3.org/Protocols/HTTP/HTRESP.html for detailled
information about HTTP status codes.
The $data_callback parameter, if used, is a way to filter the data
as it is received or to handle large transfers. It must be a
function reference, and will be passed: a reference to the instance
of the http request making the callback, a reference to the current
block of data about to be added to the body, and the $cbargs
parameter (which may be anything). It must return either a reference
to the data to add to the body of the document, or undef.
If set_callback is used, $data_callback and $cbargs are not used.
$cbargs may be either a scalar or a reference.
The data_callback is called as: &$data_callback( $self, $dataref,
$cbargs )
An example use to save a document to file is:
# Write the data to the filehandle $cbargs
sub savetofile {
my ($self,$phase,$dataref,$cbargs) = @_;
print $cbargs $$dataref;
return undef;
}
$url = "$testpath/bigbinary.dat";
open OUT, '>','bigbinary.dat';
$res = $http->request($url, \&savetofile, OUT);
close OUT;
set_callback ( $functionref, $dataref )
At various stages of the request, callbacks may be used to modify
the behaviour or to monitor the status of the request. These work
like the $data_callback parameter to request(), but are more
verstaile. Using set_callback disables $data_callback in request()
The callbacks are called as: callback ( $self, $phase, $dataref,
$cbargs )
The current phases are:
connect - connection has been established and headers are being
transmitted.
content-length - return value is used as the content-length. If undef,
and prepare_post() was used, the content length is
calculated.
done-headers - all headers have been sent
content - return value is used as content and is sent to client. Return
undef to use the internal content defined by prepare_post().
content-done - content has been successfuly transmitted.
data - A block of data has been received. The data is referenced by
$dataref. The return value is dereferenced and replaces the
content passed in. Return undef to avoid using memory for large
documents.
done - Request is done.
prepare_post ( $hashref )
Takes a reference to a hashed array of post form variables to
upload. Create the HTTP body and sets the method to POST.
http11_mode ( 0 | 1 )
Turns on or off HTTP/1.1 support. This is off by default due to
broken HTTP/1.1 servers. Use 1 to enable HTTP/1.1 support.
add_req_header ( $header, $value )
get_req_header ( $header )
delete_req_header ( $header )
Add, Delete, or a HTTP header(s) for the request. These functions
allow you to override any header. Presently, Host, User-Agent,
Content-Type, Accept, and Connection are pre-defined by the
HTTP::Lite module. You may not override Host, Connection, or Accept.
To provide (proxy) authentication or authorization, you would use:
use HTTP::Lite;
use MIME::Base64;
$http = HTTP::Lite->new;
$encoded = encode_base64('username:password');
$http->add_req_header("Authorization", $encoded);
NOTE: The present implementation limits you to one instance of each
header.
body
Returns the body of the document retured by the remote server.
headers_array
Returns an array of the HTTP headers returned by the remote server.
headers_string
Returns a string representation of the HTTP headers returned by the
remote server.
get_header ( $header )
Returns an array of values for the requested header.
NOTE: HTTP requests are not limited to a single instance of each
header. As a result, there may be more than one entry for every
header.
protocol
Returns the HTTP protocol identifier, as reported by the remote
server. This will generally be either HTTP/1.0 or HTTP/1.1.
proxy ( $proxy_server )
The URL or hostname of the proxy to use for the next request.
status
Returns the HTTP status code returned by the server. This is also
reported as the return value of *request()*.
status_message
Returns the textual description of the status code as returned by
the server. The status string is not required to adhere to any
particular format, although most HTTP servers use a standard set of
descriptions.
reset
You must call this prior to re-using an HTTP::Lite handle, otherwise
the results are undefined.
local_addr ( $ip )
Explicity select the local IP address. 0.0.0.0 (default) lets the
system choose.
local_port ( $port )
Explicity select the local port. 0 (default and recommended) lets
the system choose.
method ( $method )
Explicity set the method. Using prepare_post or reset overrides this
setting. Usual choices are GET, POST, PUT, HEAD
EXAMPLES
# Get and print out the headers and body of the CPAN homepage
use HTTP::Lite;
$http = HTTP::Lite->new;
$req = $http->request("http://www.cpan.org/")
or die "Unable to get document: $!";
die "Request failed ($req): ".$http->status_message()
if $req ne "200";
@headers = $http->headers_array();
$body = $http->body();
foreach $header (@headers)
{
print "$header$CRLF";
}
print "$CRLF";
print "$body$CRLF";
# POST a query to the dejanews USENET search engine
use HTTP::Lite;
$http = HTTP::Lite->new;
%vars = (
"QRY" => "perl",
"ST" => "MS",
"svcclass" => "dncurrent",
"DBS" => "2"
);
$http->prepare_post(\%vars);
$req = $http->request("http://www.deja.com/dnquery.xp")
or die "Unable to get document: $!";
print "req: $req\n";
print $http->body();
UNIMPLEMENTED
- FTP
- HTTPS (SSL)
- Authenitcation/Authorizaton/Proxy-Authorization
are not directly supported, and require MIME::Base64.
- Redirects (Location) are not automatically followed
- multipart/form-data POSTs are not directly supported (necessary
for File uploads).
BUGS
Some broken HTTP/1.1 servers send incorrect chunk sizes
when transferring files. HTTP/1.1 mode is now disabled by
default.
AUTHOR
Roy Hooper
SEE ALSO
LWP RFC 2068 - HTTP/1.1 -http://www.w3.org/
COPYRIGHT
Copyright (c) 2000-2002 Roy Hooper. All rights reserved.
Some parts copyright 2009 - 2010 Adam Kennedy.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.